docstr: Return the label for time x at position pos.
docstr_tok: ["Return","the","label","for","time","x","at","position","pos","."]
code: def __call__(self, x, pos=0):
      """Return the label for time x at position pos."""
      try:
          return self.dates[round(x)].item().strftime(self.fmt)
      except IndexError:
          pass
  
file_path: matplotlib/galleries/examples/ticks/date_index_formatter.py
imports: import matplotlib.pyplot
  import numpy
  import matplotlib.cbook
  from matplotlib.dates import DateFormatter, DayLocator
  import matplotlib.lines
  from matplotlib.ticker import Formatter
label_desc: Use image node_id 2 for calling the MyFormatter obj's underlying member method code with example usage: obj.__call__(x, pos) and returns: self